Rotary pump



J n- 3, 1940. w. w. .sAvmsoN 2 7 0 ROTARY PUMP Filed Sept. 4, 19 36 2 Sheets-Sheet 1 WW 71mm Jan. 23,1940. WSON 2,187,730

ROTARY PUMP Filed Sept. 4, 1936 2 Sheets-Sheet 2 of ample dimensions rel dimensions of .lowing description Patented Jan. 23, 1940 PATENT oFFicE ROTARY PUMP William Ward Davidson, Evanston, Ill.

Application September Claims.

This invention relates to improvements in rotary pumps and has special relation to pumps or compressors especially adapted for use in small refrigerating systems.

- The object of the invention is to provide a pump consisting of but few parts which shall all be sturdy and capable of withstanding the wear incident to use under relatively high pressures; and in which the power operated members shall have ample bearing surfaces not limited by the the pump cylinder.

A particular object of the invention is to provide a pump of this character in which the bearing of the rotor is not limited as to length by the axial dimensions of the cylinder but can be made tively to the pressures to be withstood.

The invention resides in a pump embodying the structural features by which the objects of the invention are attained and the invention will be more readily understood by reference to the accompanying drawings, forming part of this specification taken. in conjunction with the foland the appended claims.

In said drawings- Fig. 1 is a central vertical section of a pump embodying my invention in a preferred form and taken substantially on the line 1-! of Fig. 2;

Fig. 2 is a horizontal section on substantially the line 2-2 of Fig. 1;

Fig. 3 is a top plan view of the inner and outer pump members similar to that shown in Fig. 2 except that the inner member is shown in a diametricallyopposite'position tothat shown in- Fig. 2; and

ll Fig. 4 is a fragmentary vertical sectional view on the line 4-4 of Fig. 2, and showing a side elevation of the inner pump member.

Thepump shown in the drawings comprises a base plate v5 having a flat top surface 6 upon which the several parts ofthe pump are secured.

The pump itself comprises an outer cylindrical member 1 and an inner cylindrical member 8, the cylinder being closed at the lower end by a head 9 which serves as means for securing the pump to the base plate 5 as by screws 10, and closed at its upper end by a head I I secured to the cylininder I by screws I2. The lower head 9 is secured to the cylinder I by screws IS.

The inner pump member or planetary piston 8 is smaller in diameter than the bore of the cylinder 1 and is arranged in eccentric tangential relation thereto thus providing a crescent shaped pumping chamber ll. The inner member 8 of the pump is given a planetary motion within the 4, 1936, Serial No. 99,411

cylinder 1; that is, one point in its periphery is concentric ment of the inner member there is provided a flexible connection between the inner end portion of the partition and the inner pump member which comprises a cylindrical plug I 6 mounted in a cylindrical opening I! in the outer edge of the inner member axially of the pump. her is provided with This cylindrical plug mema longitudinal radial slot H3 in which to receive the partition l5 and permit the inner member to slide in and out on the partition as it is given the planetary movement spoken of.

For mounting the inner member to produce the planetary movement and to apply power thereto to operate the pump I provide a shank is of substantial diameter, preferably formed integrally with the inner member ,8, arranged centrally thereof and extending upwardly therefrom. It should be noted that this shank has the same ec-' centric relation to the bore of the cylinderas that of the inner member 8. This shank l9 forms the bearing member for the inner pump member and by which the inner pump member is retained in its tangential relation to the bore of the cylinder against the pressures to which it is subjected in use.

It should be understood that by extending this hearing shank out through one of the cylinder heads I am not limited by the dimensions of the pump cylinder in making this hearing shank as large in diameter and as long as may be neces sary to reduce the pressure per unit of area to such a point that the pump will operate substantially continuously without detriment or und wear.

For mounting this shank for use I provide a rigid bearing nozzle centrally arranged on and extending up from the upper cylinder head H and having a' bore 2| concentric with the cylinder bore. This bore 2| is of course eccentric to the shank l8 and I provide a vertical cylindrical shaft 22 the lower end portion of which extends down within the bearing nozzle 20 being mounted for rotation therein within a concentric sleeve 23 of suitable bearing metal. The lower end por- 8 and which plug extends tion of the shaft 22 is provided with a longitudinal bore 24 of a size to receive the shank I! and permit it to rotate freely therein. The bore 24 has of course the same eccentricity to the bore 2i as that between the inner and outer pump members.

22 extends upwardly and its upper end is rotatably mounted in a bearing ,25 which is carried by an open frame 25 which extends downwardly around the pump and has a base rin 21 secured on the base plate 5 by bolts 28.

As shown the bearing 25 consists of a ball bearing having an inner ball race 29 secured to the shaft 22 between a shoulder 30 on the shaft and a screw threaded n t 3|, also an outer ball race 32 rigidly secured on the supporting frame or bracket 26, by a plate 33 and screws 33'.

I preferably drive the pump by an electric motor and as shown in the drawings the rotor 34 of the motor is secured directly on the shaft 22 and the field or stator 35 is carried by the frame 26 which is large enough to extend around same.

Between the motor rotor and the upper end of the pump bearing 20 the shaft 22 carries a spacer collar 36. The arrangement of the several bearings is such that when power is applied by the motor to drive the shaft 22, the shank I9 is carried around in a circular orbit concentric with the bore of the pump cylinder, that is the shaft 22 rotates around the shank but due to the eccentric relation the planetary movement of the inner pump member is produced.

In order that the pump may operate substantially continuously without detriment, the pump and its motor is enclosed beneath a dome 31 which has a base ring base 5 by bolts 39. A packing ring may be arranged on the base 5 below the dome for readily making the joint between the two pressure tight.

A supply passage II for the fluid to be compressed enters the cylinder at one side of the partition l5 and a discharge passage 42 leads from the cylinder at the opposite side of the partition. The inlet or supply passage extends through the lower cylinder head 9 and into the base 5 and preferably extends out to the periphery of same 43 Fig. 2 so that it can be connected to any suitable source of supply. The discharge passage 42 leads through the wall of the cylinder 1 and a suitable check valve 44 is provided to prevent the return of the compressed fluid to the cylinder.

Preferably a discharge pipe 45 is provided which is arranged to deliver the compressed fluid into the upper part of the dome 31.

The compressed-fluid maybe discharged from the dome through any suitable connection not shown, for conducting it to a suitable place for use.

I make use of the lower part of the dome as a reservoir to contain oil 45 for lubricating the various bearings and I provide ducts connecting the various bearings with the oil.

For this purpose the bearing nozzle 20 is provided with a radial hole 41 which extends through the sleeve 23 and delivers oil to a circumferential groove 48 in the outer surface of the shaft 22, the inner surface of the sleeve being provided with a longitudinal oil groove 49 through which oil is delivered to the top of the bearing nozzle 20.

For oiling the shank IS the shaft 22 has a radial oil passage leading from the groove 48 to a short longitudinal groove 50 in the wall of the bore 24 and the shank I9 has a spiral oil groove 5| which is in communication with the groove 50.

spiral groove 5| shank and the oil is delivered to the opposed surfaces of the inner and outer pump members at the top of the chamber and works through this joint extends the full length of the and lubricates the partition and its flexible connection to the inner pump member.

It also rises to the top of the shank and there is a longitudinal oil passage 52 in the shaft 22 extending from the top of the bore 24 to the top of the shaft and oil overflows through this opening and flows down to the ball bearing 25 at the upper end of the shaft 22.

Also an oil passage 53 extends through the lower cylinder head 9 and enters the cylinder to lubricate the lower end of the inner pump member and assist in lubricating the partition.

By means of my improved construction I am enabled to provide such ample bearings and such a sturdy structure that the slight lack of rotational balance does not cause perceptible wear but the pump can be indefinitely operated substantially continuously without undue wear or heating.

As many modifications of the invention will readily suggest themselves to one skilled in the art I do not limit or conflne the invention to the specific details of construction or operation herein shown and described.

I claim:

1. In a rotary pump, pump members including a hollow cylindrical member, a piston member mounted therein in eccentric tangential relation, end plates rigidly secured to one of said members to form wtih the other a pump chamber, a partition for the chamber associated with the end plates and the member to which they are secured, said partition being immovably flxed relatively thereto, one of said pump members being stationary and the other movable, means for causing the movable pump member to move relative to the stationary member to produce a pumping action within the pump chamber, and bearing means including a shank rigid with the movable pump member and extending outside of the space between the end plates whereby ample support may be provided for the shank to directly take the force of compression.

.2. In a rotary pump, pump members including a hollow cylindrical member, a piston ,member mounted therein in eccentric tangential relation, end plates rigidly secured to one of said members to form with the other a pump chamber, a partition for the chamber associated with the end plates and the member to which they are secured, said partition being immovably flxed relatively thereto, one of said pump members being stationary and the .other movable, means for causing the movable pump member to move relative to the stationary member to produce a pump ing action within the pump chamber, and bearing means including a shank rigid with the movable pump member and extending outside of the space between the end plates whereby ample support may be provided for the shank to directly take the force of compression, said bearing means having a total length which is substantially in excess of the width of the pump chamber.

3. In a rotary pump, pump members including a hollow cylindrical member, a piston member mounted therein in eccentric tangential relation, end plates rigidly secured to one of said members to form with the other a pump chamber, a partition associated with the end plates and the member to which they are secured, said parti- I tion being immovably flxed relatively thereto m able pump member and ing shaft havingan eccentric bearing recess exhaving a rocking and sliding engagement with the other member, one of said pump members being stationary and the other movable, means for causing the movable pump member to move relative to the stationary member to produce a pumping action within the pump chamber, and bearing means including a shank rigid with the movextending outside of the space between the end plates whereby ample support may be provided for the shank to directly take the force of compression, saidmeans formoving the movable pump member including a rotatable shaft having eccentric telescopic engage-- ment with the extended shaft, and bearing means for the shaft overlapping the telescopic engagement of the shank with the shaft.

4. In a rotary pump, pump members including a stationary hollow cylindrical member, a piston member mounted therein in eccentric tangential relation, end plates rigidly secured to one of said members to form with the other a pump chamber, a-partition for the chamber associated with the end plates and the member to which they are secured, said partition being immovably fixed relative thereto and having a rocking and sliding engagement with the other member, means for causing the piston member to partake of a planetary movement within the stationary cylindrical member, said means comprising a driving shaft having an eccentric bearing recess extending axially therein and a shank fixed with respect to the piston member extending into said recess for a distance greater than the spacing of the end plates, and bearing means for the shaft overlapping the telescopic engagement of the shank with the shaft.

5. In a rotary pump, pump members including a stationary hollow cylindrical member, a piston member mounted therein in eccentric tangential relation, end plates rigidly secured to one of said members to form with the other a pump chamber, a partition for the chamber associated with the end plates and the member to which they are secured, said. partition being immovably fixed relative thereto and having a rocking and sliding engagement with the other member, means for causing the piston member to partake of a planetary movement within the stationary cylindrical member, said means comprising a drivtending axially into the shaft, a shank fixed with respect to the piston member extending into said recess, @and a bearing for the driving shaft fixed.

with respect to the stationary cylindrical mem- 1 her and engaging the driving shaft at the portion thereof which forms a bearing for the shank.

6. A rotary pump of the general type comprising pump members including a hollow cylinder, a piston mounted therein in eccentric tangenti'al relation, end plates forming'rigid portions of one pump member and forming with the other a pump chamber, a partition associated with both of the pump members at substantially fixed points thereon, one of the pump members being stationmovable, and means for im-,

of the movable memjournaled at one -tions of one pump member and '7. A rotary pump of the general type comprising pump members including a hollow cylinder, a piston mounted therein in eccentric tangential relation, end plates forming rigid porforming with the other a pump chamber, a partition associated with both of the pump members at substantially fixed points therein, one of the pump members being stationary and the other movable, and means for imparting a planetary movement to the movable member to produce a pumping action within the pump chamber including a drive shaft journaled at one side of the pump, characterized by the provision of a bearing extending adjacent to the body portion of the movable member, and having the drive shaft journaled therein, and a shank rigid with the body portion of the movable member and extending within the bearing and journaled within the drive shaft, the length of the journaled portion of the shank being greater than the distance between the end plates.

8. A rotary pump of the general type comprising to the movable member to produce a. pumping action within the pump chamber including a drive shaft journaled at one pump members being stationary and the other being movable but confined by the end plates to movements in directions within a plane, and means for imparting a planetary movement to the movable member to produce a pumping action within the pump chamber including a drive shaft side of the pump, characterized by the provision of a rigid body portion as part member, a shank by the body portion and journaled in the drive shaft, and a bearing extending to a position adjacent to the movable member and journaling at due to the forces shaft.

10. A rotary pumpadapted-to operate by rotation about a vertical axis, including a casing having a body of oil therein, pump members submerged in the oil, and including a hollow cylindrical member, a piston member mounted there! rigidly carried applied thereto by the drivein in eccentric tangential relation therewith, end plates rigidly secured to one of said members to form with the other a pump chamber, a parchamber and means for imparting a planetary movement to one of the pump members including a vertically disposed drive shaft above the said pump member having a bearing above the oil level and a bearing below the oil level, and a shank rigidly carried by the driven pump member and eccentrically journaled in the lower end of the shaft, the shaft and for the shaft.

WM. WARD DAVIDSON. 

